The motor looks awesome. Its totally up to your preference but that large cover over the flywheel can be removed. These are stationary engines so they have the shroud to cool the engine, and seeing as your fitting it to a bike and will be in motion it isnt necessary. And depending on the flywheel, some have sharp teeth to catch the air to cool the engine. These teeth can be machined smooth so to not cause injury.
If it was me id remove the cover to expose that beautiful engine, and have the flywheel smoothed. But then again it still looks good as it is, and itll be less work and you wont be changing the engine from original, should you choose to sell it in the future, or if they go up in value.
Just a thought, maybe you could get your friend to build this bike for you but you should help him out, it may be cheaper, and you will learn lots and when you get this thing going chances are you will want to build another